Milwaukee City Wire

Milwaukee Formations are geological features that are unique to the local Milwaukee area.

According to TMJ4 News, Milwaukee Formations are a group of rocks and fossils found in Milwaukee County and Ozaukee County. The rocks are at least 390 million years old, which pre-dates even the dinosaurs. The fossils consists of marine organisms which inhabited Wisconsin when it was covered by a shallow ocean eons ago, TMJ4 News reported.

"The types of fossils in the ecosystem that (were) here is different from the entire region in the Midwest where the same rocks are found," Scott Schaefer, the collections manager at the Weis Earth Science Museum in Menasha, told TMJ4 News. "You can hand me 10 fossils from our package of rocks and I will be able to exclusively (know it is a) Milwaukee Formation, not the Devonian of New York, Michigan or elsewhere."

Milwaukee Formations exhibit an incredibly high yet unique biodiversity found within each rock.

“It's a shell creature found only in our rocks here. So if you were to hand me a fossil that has that organism in it, I would be able to tell that it's from Milwaukee," Schaefer said.

Visitors can view a collection of Milwaukee Formations at the Thomas A. a Greene Geological Gallery at University of Wisconsin-Milwaukee.